Bulg. J. Phys. vol.19 no.3-4 (1992), pp. 060-066



On the Magnetic Phase Diagram of CoAlCr

K. Eftimova1, R. Laiho1, E. Lähderanta1, J. Booth2
1Wihuri Physica Laboratory, Turku University, Turku 20 500, Finland
2Physics Department, University of Salford, Salford M 5 4WT, UK
Abstract. Low-field (up to 5 Oe) magnetic measurements are performed in 4.2-200 K temperature range for CoAlCr ternary alloys. Cr is substituted for Al and is 2.5, 5, 10 and 20 at.%. It is investigated that the influence of the AFM Cr on the magnetic properties of the parent CoAl alloy is analogous to that of a FM dopant as Co for example. With increasing the Cr concentration, the PM CoAl alloys evolve from a characteristic spin-glass behaviour to a magnetic reentrant magnetic state (mixed state M) that signifies the onset of ferromagnetic order at certain temperatures. The mixed state manifests a spontaneous ferromagnetic moment, that persists partly during the transition to the SG-like state while the field cooled magnetization of the M-state reveals unidirectional magnetic anisotropy of a spin-glass. Sensitive SQUID magnetic measurements proved the alloys with XCr ≤ 10 at.% Cr to be a single phase.

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