Collapse of ferromagnetism in itinerant-electron system: A magnetic, transport properties, and high pressure study of (Hf,Ta)Fe{sub 2} compounds
- Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France)
- Institute of Physics AS CR v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic)
The magnetism and transport properties were studied for Laves (Hf,Ta)Fe{sub 2} itinerant-electron compounds, which exhibit a temperature-induced first-order transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) state upon heating. At finite temperatures, the field-induced metamagnetic phase transition between the AFM and FM has considerable effects on the transport properties of these model metamagnetic compounds. A large negative magnetoresistance of about 14% is observed in accordance with the metamagnetic transition. The magnetic phase diagram is determined for the Laves Hf{sub 1−x}Ta{sub x}Fe{sub 2} series and its Ta concentration dependence discussed. An unusual behavior is revealed in the paramagnetic state of intermediate compositions, it gives rise to the rapid increase and saturation of the local spin fluctuations of the 3d electrons. This new result is analysed in the frame of the theory of Moriya. For a chosen composition Hf{sub 0.825}Ta{sub 0.175}Fe{sub 2}, exhibiting such remarkable features, a detailed investigation is carried out under hydrostatic pressure up to 1 GPa in order to investigate the volume effect on the magnetic properties. With increasing pressure, the magnetic transition temperature T{sub FM-AFM} from ferromagnetic to antiferromagnetic order decreases strongly non-linearly and disappears at a critical pressure of 0.75 GPa. In the pressure-induced AFM state, the field-induced first-order AFM-FM transition appears and the complex temperature dependence of the AFM-FM transition field is explained by the contribution from both the magnetic and elastic energies caused by the significant temperature variation of the amplitude of the local Fe magnetic moment. The application of an external pressure leads also to the progressive decrease of the Néel temperature T{sub N}. In addition, a large pressure effect on the spontaneous magnetization M{sub S} for pressures below 0.45 GPa, dln(M{sub s})/dP = −6.3 × 10{sup −2 }GPa{sup −1} was discovered. The presented results are consistent with Moriya's theoretical predictions and can significantly help to better understand the underlying physics of itinerant electron magnetic systems nowadays widely investigated for both fundamental and applications purposes.
- OSTI ID:
- 22308164
- Journal Information:
- Journal of Applied Physics, Vol. 116, Issue 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
ATOMIC FORCE MICROSCOPY
CRITICAL PRESSURE
ELECTRIC CONDUCTIVITY
FERROMAGNETISM
FLUCTUATIONS
HAFNIUM COMPOUNDS
INTERMETALLIC COMPOUNDS
IRON COMPOUNDS
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETIZATION
MAGNETORESISTANCE
PARAMAGNETISM
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PRESSURE RANGE GIGA PA
TANTALUM COMPOUNDS
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE