Antiferromagnetic phase transitions in an ordered Pt3Fe(111) film studied by neutron diffraction


Neutron diffraction has been used to investigate the critical behavior at the onset of antiferromagnetic phase transitions in a (111) oriented Pt73Fe27 film grown on an a-axis oriented sapphire (alpha-Al2O3) substrate. As in the bulk, there is an antiferromagnetic reorientation transition from the Q(1)=2pi/a(1/2,1/2,0) phase to the Q(2)=2pi/a(1/2,0,0) phase upon cooling. The temperature dependence of the integrated intensity of the (1/2,1/2,0) and the (1/2,0,0) antiferromagnetic Bragg peaks yielded the Neeel temperature of 160.25+/-0.2 K and a reorientation transition temperature of 95+/-0.2 K. The magnetization critical exponent beta is found to be 0.368+/-0.013 for the Q(1) phase and 0.37+/-0.02 for the Q(2) phase. These critical exponents are in excellent agreement with the predictions of the 3d Heisenberg universality class. A comparison of the transition temperatures and the exponents in the film and in single crystal at the same alloy composition is presented.

CRITICAL EXPONENTS, MAGNETIC ORDER, Materials Science, Multidisciplinary, Physics, Applied, Physics, Condensed Matter, Materials Science, Physics
Krishnamurthy, V., et al. (2004): Antiferromagnetic Phase Transitions in an Ordered Pt₃ Fe(111) Film Studied by Neutron Diffraction. Physical Review B, 70(2).DOI: