Control of metamagnetic phase transition in epitaxial FeRh films by changing atomic order degree

•The first-order phase transition parameters (transition temperature, transition temperature range, and thermal hysteresis width) of epitaxial FeRh films can be adjusted to a great extent through changing the growth temperature, annealing temperature, and annealing time.•The increase of annealing temperature reduces the displacement of Fe (Rh) atoms, which maybe the reason for controlling the magnetic phase transition parameters. Near-equiatomic FeRh alloys undergo a first-order metamagnetic phase transition around room temperature. Here, we show that the phase transition parameters of epitaxial FeRh films can be adjusted to a great extent through changing the growth temperature, annealing temperature, and annealing time. The influences of the surface morphology and Fe (Rh) element distribution before and after heat treatments have been analyzed. The experimental results show that the increase of annealing temperature reduces the displacement of Fe (Rh) atoms. As a result, the resistivity is reduced, the phase transition interval is narrowed, and the phase transition is shifted to high temperature. The experimental results indicate that the first-order phase transition parameters in epitaxial FeRh films can be controlled by heat treatments and are correlated with the atomic order degree of Fe (Rh).