Magnetic Phase Transitions in Itinerant Electron Magnets Hf1-xTaxFe₂

Magnetic phase transitions in itinerant electron magnets Hf 1- x Ta x Fe 2 have been studied from measurements of Mössbauer effect, magnetization and X-ray diffraction. The first order magnetic phase transition from ferromagnetic to antiferromagnetic state has been observed with increasing temperature in the Ta concentration range 0.1< x <0.3. It is concluded that the magnetic phase transitions in Hf 1- x Ta x Fe 2 can be interpreted in terms of the recent theoretical result by Moriya and Usami on magnetic phase transitions in itinerant electron systems.