An investigation of the magnetic properties of Fe-Mn-Zr, Fe-R-Zr (R = La, Pr, Gd, Dy) melt spun alloys and Mn-Ge thin films

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6754502

Nicolaides, G K

The magnetic properties of Fe{sub 90-x}Mn{sub x}Zr{sub 10} (x = 0.2-22) and Fe{sub 90-x}R{sub x}Zr{sub 10} (x = 0.3-6) (R = La, Pr, Gd, Dy) melt spun alloys and of Ge{sub 100-x} Mn{sub x} (x = 10, 20, 64) thin films have been investigated using ac and dc magnetic techniques in the temperature range of 4.2-330K. In addition, electron microscopy was used to investigate the microstructure of the Mn-Ge thin films. The ac susceptibility results show that the Fe-Mn-Zr and Fe-R-Zr systems exhibit a double transition behavior with decreasing temperature. The first transition occurs at T{sub c} {approximately} 230K and has been found to be a PM to FM one, while at a lower temperature T{sub f} {approximately} 300K another transition occurs from a FM-like phase to a SG-like phase. Low field hysteresis loop studies show some spin-glass characteristics. In addition from the magnetic phase diagram it was found that in the Fe-Mn-Zr system, Mn contents up to 1.2 at % enhance the FM phase while large Mn concentrations enhance the SG-like phase. However similar studies in the Fe-R-Zr system indicate that the lower transition at T{sub f} is very sensitive to rare earth substitutions. La and Gd enhanced the FM-like phase while Pr and Dy enhance the SG-like phase. A scaling analysis performed near the PM-FM transition on the Fe-Mn-Zr system gives exponents which deviate slightly from the ones predicted by a 3d-Heisenberg model. The above results indicate that the transition at T{sub f} is due to a magnetic hardening process. The magnetic studies studies of Mn-Ge films in the amorphous state show a spin glass behavior, while heat treated films showed a ferromagnetic behavior. Electron microscopy studies of these films show the existence of the Mn{sub 5}Ge{sub 3} intermetallic phase in a heat treated X= 64 sample.

• Research Organization: Kansas State Univ., Manhattan, KS (USA)
• OSTI ID: 6754502
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360104* -- Metals & Alloys-- Physical Properties
ALLOY SYSTEMS
ALLOYS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIAGRAMS
DYSPROSIUM ALLOYS
ELECTRON MICROSCOPY
ELEMENTS
FILMS
GADOLINIUM ALLOYS
GERMANIUM
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
LANTHANUM ALLOYS
MAGNETIC PROPERTIES
MAGNETIC RIGIDITY
MAGNETIC SUSCEPTIBILITY
MANGANESE ALLOYS
METALLURGICAL EFFECTS
METALS
MICROSCOPY
MICROSTRUCTURE
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRASEODYMIUM ALLOYS
RARE EARTH ALLOYS
TEMPERATURE DEPENDENCE
TERNARY ALLOY SYSTEMS
ZIRCONIUM ALLOYS