Method and apparatus for measuring characteristics of ferromagnetic tunnel magnetoresistance effect element, and hard disk drive

A method for measuring characteristics of a tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween, wherein said method comprises the steps of:

• setting an initial current value I0 which does not destroy the element to be measured;
• measuring a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in a laminate direction, and defining, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• measuring a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defining, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, an inspection current value Is (Is=Vs/R2);
• and
• measuring the characteristics of the element by applying the current of value Is in the laminate direction,
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

A method for measuring characteristics of a tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween, wherein said method comprises the steps of:

• setting an initial current value I0 which does not destroy the element to be measured;
• measuring a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in a laminate direction, and defining, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• measuring a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defining, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a second modified current value I2 (I2=Vs/R2);
• measuring a third resistance value R3 as an approximate resistance value of the element by applying the current of value I2 in the laminate direction, and defining, based on said third resistance value R3 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, an inspection current value Is (Is=Vs/R3);
• and
• measuring the characteristics of the element by applying the current of value Is in the laminate direction,
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

A method for measuring characteristics of a tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween, wherein said method comprises the steps of:

• (1) setting an initial current value I0 which does not destroy the element to be measured;
• (2) measuring a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in a laminate direction, and defining, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• (3) measuring a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defining, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a second modified current value I2 (I2=VS/R2);
• (4) measuring a third resistance value R3 as an approximate resistance value of the element by applying the current of value I2 in the laminate direction, and defining, based on said third resistance value R3 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a third modified current value I3 (I3=Vs/R3);
• (5) repeating a step which is substantially identical to the step (4) so as to measure a (n+1)th resistance value Rn+1 as an approximate resistance value of the element by applying a nth modified current of value In (wherein n is an integer greater than or equal to 4) in the laminate direction, and defining, based on said (n+1)th resistance value Rn+1 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, an inspection current value Is (Is=Vs/Rn+1);
• and
• (6) measuring the characteristics of the element by applying the current of value Is in the laminate direction,
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

An apparatus for measuring characteristics of a tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said apparatus having a processing circuit which is capable of measuring characteristics of said element while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction which is set not to destroy the element to be measured, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• measures a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defines, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, an inspection current value Is (Is=Vs/R2);
• and
• measures the characteristics of the element by applying the current of value Is in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

An apparatus for measuring characteristics of a tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said apparatus having a processing circuit which is capable of measuring characteristics of said element while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• measures a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defines, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a second modified current value I2 (I2=Vs/R2);
• measures a third resistance value R3 as an approximate resistance value of the element by applying the current of value I2 in the laminate direction, and defines, based on said second resistance value R3 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, an inspection current value Is (Is=Vs/R3);
• and
• measures the characteristics of the element by applying the current of value Is in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

An apparatus for measuring characteristics of a tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said apparatus having a processing circuit which is capable of measuring characteristics of said element while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• (1) measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction which is set not to destroy the element to be measured, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• (2) measures a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defines, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a second modified current value I2 (I2=Vs/R2);
• (3) measures a third resistance value R3 as an approximate resistance value of the element by applying the current of value I2 in the laminate direction, and defines, based on said second resistance value R3 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a third modified current value I3 (I3=Vs/R3);
• and
• (4) repeats a step which is substantially identical to the step (3) so as to measure a (n+1)th resistance value Rn+1 as an approximate resistance value of the element by applying a nth modified current of value In in the laminate direction (wherein n is an integer greater than or equal to 4), and defines, based on said (n+1)th resistance value Rn+1 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, an inspection current value Is (Is=Vs/Rn+1);
• and
• (5) measures the characteristics of the element by applying the current of value Is in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

A hard disk drive having, at a tip of a suspension, a tunnel magnetoresistance effect element for deriving a magnetic signal from a magnetic recording hard disk, said tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said hard disk drive having a processing circuit which is capable of deriving a magnetic signal while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction which is set not to destroy the element to be measured, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a sense current value Ise (Ise=Vs/R1);
• and
• derives a magnetic signal by applying the current of value Ise in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

A hard disk drive having, at a tip of a suspension, a tunnel magnetoresistance effect element for deriving a magnetic signal from a magnetic recording hard disk, said tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said hard disk drive having a processing circuit which is capable of deriving a magnetic signal while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction which is set not to destroy the element to be measured, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• measures a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defines, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a sense current Ise (Ise=Vs/R2);
• and
• derives a magnetic signal by applying the current of value Ise in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

A hard disk drive having, at a tip of a suspension, a tunnel magnetoresistance effect element for deriving a magnetic signal from a magnetic recording hard disk, said tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said hard disk drive having a processing circuit which is capable of deriving a magnetic signal while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction which is set not to destroy the element to be measured, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• measures a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defines, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a second modified current I2 (I2=Vs/R2);
• measures a third resistance value R3 as an approximate resistance value of the element by applying the current of value I2 in the laminate direction, and defines, based on said third resistance value R3 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a sense current value Ise (Ise=Vs/R3);
• and
• derives a magnetic signal by applying the current of value Ise in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.

A hard disk drive having, at a tip of a suspension, a tunnel magnetoresistance effect element for deriving a magnetic signal from a magnetic recording hard disk, said tunnel magnetoresistance effect element having a tunnel multilayered film comprising a tunnel barrier layer which is a thin insulation film which allows electrons to pass therethrough while keeping spins of the electrons due to the tunnel magnetoresistance effect and a first and a second ferromagnetic layer formed to sandwich said tunnel barrier layer therebetween,

• said hard disk drive having a processing circuit which is capable of deriving a magnetic signal while supplying a sense current in a lamination direction of the tunnel multilayered film for applying a given voltage,
• wherein said processing circuit
• (1) measures a first resistance value R1 as an approximate resistance value of the element by applying the current of value I0 in the laminate direction which is set not to destroy the element to be measured, and defines, based on said first resistance value R1 and a voltage value Vs which is a constant voltage value as a measurement standard for the element, a first modified current value I1 (I1=Vs/R1);
• (2) measures a second resistance value R2 as an approximate resistance value of the element by applying the current of value I1 in the laminate direction, and defines, based on said second resistance value R2 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a second modified current I2 (I2=Vs/R2);
• (3) measures a third resistance value R3 as an approximate resistance value of the element by applying the current of value I2 in the laminate direction, and defines, based on said third resistance value R3 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a third modified current value I3 (I3=Vs/R3);
• and
• (4) repeats a step which is substantially identical to the step (3) so as to measure a (n+1)th resistance value Rn+1 as an approximate resistance value of the element by applying a nth modified current of value In in the laminate direction (wherein n is an integer greater than or equal to 4), and defines, based on said (n+1)th resistance value Rn+1 and the voltage value Vs which is the constant voltage value as the measurement standard for the element, a sense current value Ise (Ise=Vs/Rn+1);
• and
• (5) derives a magnetic signal by applying the current of value Ise in the laminate direction, and
• wherein said initial current value I0 is set to be in the range of 1 μA to 2.3 mA.