Inhomogeneous compounds having high magnetic resistance, the production and use thereof

• US 20110135960A1
• Filed: 05/20/2009
• Published: 06/09/2011
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Johannes Gutenberg-Universitã¤T Mainz
• Original Assignee: Johannes Gutenberg-Universitã¤T Mainz
• Inventors: Casper, Frederick, Felser, Claudia
• Granted Patent: US 8,277,960 B2
• Time in Patent Office: Days
• US Class Current: 428/810
• CPC Class Codes: H01F 1/408 half-metallic, i.e. having only one electronic spin direction at the Fermi level, e.g. CrO2, Heusler alloys H01F10/1936 takes precedence
• CPC Class Codes: H10N 50/85 Magnetic active materials
• CPC Class Codes: Y10T 428/11 Magnetic recording head
• CPC Class Codes: Y10T 428/115 Magnetic layer composition
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

The invention relates to inorganic, intermetallic, inhomogeneous compounds having a magnetic resistance effect and an intrinsic field sensitivity of at least 7% at 1 T at room temperature. The invention further relates to a method for the production and use thereof, particularly as magnetic field sensors or in spin electronics.

Claims

1. An inhomogeneous inorganic compound containing an overall phase system comprising a main phase and at least one secondary phase, of which

the main phase is an intermetallic compound,

wherein the intermetallic compound

has at least three elements per formula unit,

is semiconducting or has a metal-semiconductor transition,

has a magnetoresistance with an intrinsic field sensitivity of at least 0.1% per 0.1 T,

has cubic symmetry with a maximum structural distortion of 10%

belongs to half-Heusler phases

has 8 or 18 valence electrons and

is paramagnetic

and wherein the secondary phase

is metallic and comprises at least one element which occurs in the intermetallic compound.

2. The compound as claimed in claim 1, wherein the main phase constitutes at least 70 wt % of the overall phase system.

3. The compound as claimed in claim 1, wherein at least one secondary phase is distributed randomly in the main phase.

4. The compound as claimed in claim 1, wherein said compound has a magnetoresistance effect above 23°

C.

5. The compound as claimed in claim 1, wherein the intermetallic compound is a lutetium or lanthanum compound with a group VIIIb element and a metal or semimetal of main group V.

6. The compound as claimed in claim 1, wherein the intermetallic compound is a lutetium or lanthanum compound with a group Ib element and a metal or semimetal of main group IV.

7. The compound as claimed in claim 5, wherein the intermetallic compound is LuNiBi, LuPtBi, LuPdBi, LuNiSb, LuPdSb, LuPtSb, LaPtBi or LaPdBi.

8. The compound as claimed in claim 6, wherein the intermetallic compound is LuAuSn or LuAuPb.

9. The compound as claimed in claim 1, wherein the magnetoresistance MR is positive.

10. A method for producing an inhomogeneous compound as claimed in claim 1 comprising combining three different elements to form the compound, at least one element present in excess,

wherein the type and amount of the elements selected form compounds in which

the resulting compound is cubically crystallized with a maximum lattice parameter distortion of 10%,

the compound belongs to half-Heusler phases,

the compound is semiconducting or has a metal-semiconductor transition,

the compound has a magnetoresistance with an intrinsic field sensitivity of at least 0.1% per 0.1 T,

the compound has 8 or 18 valence electrons and

the compound is paramagnetic.

11. The method as claimed in claim 10, wherein said combining step comprises melting the three elements by an arc welding device in an inert gas atmosphere.

12. Read heads in storage media comprising the compounds as claimed in claim 1.

13. The compound as claimed in claim 1, wherein the overall phase system consists of the main phase and at least one secondary phase and the secondary phase consists of at least one element which occurs in the intermetallic compound.