Annealing magnetic elements for stable mechanical properties

A method of making a magnetic element comprising the steps of:

• providing a magnetic element formed of a magnetically soft amorphous metallic material;
• first-annealing said amorphous material for at least one hour at a temperature that is below a crystallization temperature of said material;
• and
• after said first-annealing step, second-annealing said amorphous material for a time and at a temperature sufficient to crystallize the bulk of the material to give the overall magnetic material semi-hard magnetic properties.

A method of making a magnetic element comprising the steps of:

• providing a magnetic element formed of a magnetically soft amorphous metallic material;
• heating said amorphous material from room temperature to an annealing temperature that is above a crystallization temperature of said material, said heating being performed such that the rate at which the temperature of said material is increased never exceeds 0.265.degree. C./sec;
• and
• annealing said amorphous material at said annealing temperature for a time sufficient to crystallize the bulk of the material to give the overall magnetic material semi-hard magnetic properties.

An electronic article surveillance system for detecting the presence of a marker in an interrogation zone, comprising:

• a marker including a signal generating first magnetic element having an activated state in which the signal generating first magnetic element is able to interact with an applied magnetic field and a deactivated state in which the signal generating first magnetic element is disabled from interacting with said applied magnetic field and a second magnetic element disposed adjacent said signal generating first magnetic element for placing said signal generating first magnetic element in said activated and deactivated states, said second magnetic element comprising an amorphous magnetically soft iron-metalloid material at least a part of the bulk of which has been crystallized to give the overall second magnetic element semi-hard magnetic properties, said amorphous magnetically soft iron-metalloid material having been pre-annealed for at least one hour prior to crystallization, said pre-annealing at a temperature that is below a crystallization temperature of said material;
• means for transmitting said magnetic field into the interrogation zone;
• and
• means for receiving a signal resulting from said signal generating first magnetic element of said marker interacting with said magnetic field.

A method of making a magnetic element comprising the steps of:

• providing a magnetic element formed of a magnetically soft amorphous metallic material in the form of a substantially flat planar strip;
• first-annealing the strip of amorphous material at a temperature below a crystallization temperature of the material and for a time sufficient to cause a reduction of substantially 0.65 percent in a longitudinal dimension of the strip of amorphous material;
• and
• after said first-annealing step, second-annealing said amorphous material for a time and at a temperature sufficient to crystallize the bulk of the material to give the overall magnetic material semi-hard magnetic properties.