Electron spin resonance and magnetization study of magnetic dilution in the amorphous alloys Fe/sub x/Ni/sub 80-x/P/sub 14/B/sub 6/ and Fe/sub y/B/sub 100-y/ - spin glass effects and the disappearance of ferromagnetism
A spin glass is a magnetic state in which the spins are frozen in random directions because of strong competition on a local scale between ferromagnetic and antiferromagnetic order. The dynamic properties of spin glasses are not well understood. It is the purpose of this paper to study some of the dynamic properties of alloys that have strong magnetic competition. Using standard magnetic resonance techniques, two amorphous alloy series Fe/sub x/Ni/sub 80-x/P/sub 14/B/sub 6/ and Fe/sub y/B/sub 100-y/ have been studied as a function of temperature, microwave frequency, and concentration of magnetic ions. The concentration regimes studied were chosen so as to include alloys with only a paramagnet-ferromagnet (PM-FM) transition, reentrant alloys (exhibiting a PM-FM transition followed, at a lower temperature, by a ferromagnet-spin glass (FM-SG) transition), and alloys which have only a PM-SG transition. Some magnetization measurements were also made. Notable results: a-Fe/sub x/Ni/sub 80-x/P/sub 14/B/sub 6/, 1) the resonance linewidths show that the FM state (x greater than or equal to 9) has a static inhomogeneity which increases as x is reduced. In addition one notes that the spin waves soften as x is reduced. 2) For x < 9 EPR has been done for the first time on dilute Fe alloys. 3) The linewidth for each alloy which shows spin freezing (x less than or equal to 19) increases at low temperature with a unique functional dependence on temperature. For a-Fe/sub y/B/sub 100-y/: the FM state present above y approx. = 40 is unusual. For instance, the low field magnetization is not demagnetization limited.
- OSTI ID:
- 5679576
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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