US 5,510,172 A · Magnetic multilayer film and magnetoresistance element

Abstract

A magnetic multilayer film having magnetoresistance (MR) is prepared by depositing at least two magnetic thin films having different coercive forces while interposing a non-magnetic thin film therebetween. A first magnetic thin film having a lower coercive force has a squareness ratio SQ.sub.1 and a thickness t.sub.1, a second magnetic thin film having a higher coercive force has a squareness ratio SQ.sub.2 and a thickness t.sub.2, and the non-magnetic thin film has a thickness t.sub.3. A first form of the invention requires 4 .ANG..ltoreq.t.sub.2 <30 .ANG., 20 .ANG.<t.sub.1 .ltoreq.200 .ANG., t.sub.1 >t.sub.2, t.sub.3 .ltoreq.200 .ANG., 0.7.ltoreq.SQ.sub.1 .ltoreq.1.0, and 0.1.ltoreq.SQ.sub.2 .ltoreq.0.8, thereby achieving a magnetic multilayer film which shows a great MR ratio of several percents under an external magnetic field of several Oe, an excellent rise across zero magnetic field and heat resistance. A second form of the invention requires 4 .ANG.<t.sub.2 <20 .ANG., 5 .ANG.<t.sub.1 .ltoreq.20 .ANG., t.sub.1 <t.sub.2 and 32 .ANG.<t.sub.3 <50 .ANG., thereby achieving a magnetic multilayer film which is increased in MR ratio, MR slope between -50 Oe and +50 Oe, and high-frequency MR slope while showing minimized hysteresis. There are obtained MR elements, typically high sensitivity MR sensors and MR heads capable of high density magnetic recording.

Claims20

Dependent claims

A magnetic multilayer film, comprising a first and a second magnetic thin film with a non-magnetic thin film between said first and second magnetic thin films, wherein

said first and second magnetic thin films have different coercive forces, said first magnetic thin film having a lower coercive force and a squareness ratio SQ.sub.1 of from 0.7 to 1.0 and said second magnetic thin film having a higher coercive force and a squareness ratio SQ.sub.2 of from 0.1 to 0.8;
the first magnetic thin film has a thickness t.sub.1, the second magnetic thin film has a thickness t.sub.2 and the non-magnetic thin film has a thickness t.sub.3 wherein 4 .ANG..ltoreq.t.sub.2 <30 .ANG.20 .ANG.<t.sub.1 <200 .ANG., t.sub.1 >t.sub.2 and 4 .ANG.<t.sub.3 <60 .ANG., and
wherein the ratio of coercive force between adjacent magnetic thin films is 1.2:1 to 100:1.

Dependencies are inferred from the claim text.

Magnetic multilayer film and magnetoresistance element

Life of this patent

Magnetic multilayer film and magnetoresistance element

Life of this patent

Abstract

Claims20