Presentation Information
[21a-C501-4]High-quality epitaxial growth of altermagnetic RuO2 films using reactive sputtering
〇(P)Cong He1, Zhenchao Wen1, Hiroaki Sukegawa1, Seiji Mitani1 (1.National Institute for Materials Science)
Keywords:
Altermagnetic,RuO2,Epitaxial growth
RuO2 is conductive and was considered as paramagnet, but later proved to be itinerant antiferromagnet with a Néel vector of [001] and a Néel temperature above 300 K [1]. Recently, it was termed as an altermagnet where the alternating spin polarizations exist in direct physical and reciprocal momentum spaces. RuO2 was further demonstrated to enable efficient spin current generation with spin orientation along the Néel vector due to its spin splitter effect. However, detailed microstructure characterizations are lacking especially when RuO2 were grown on different substrates. Here we found single-crystalline epitaxial growth of RuO2 film was successfully achieved on Al2O3(1-102) substrates, whilst two and three kinds of domain structures were obtained on MgO(001) and Al2O3(0001), respectively. The optimal annealing temperature was 600 °C, which leads to a resistivity of 51.5 μΩ·cm, much lower than those in previous studies. STEM observations reveal that the film was highly crystalline and had an epitaxial relationship of RuO2(101)[010] // Al2O3(1-102)[110]. Temperature dependence of resistivity measurement indicates a Néel temperature of ~390 K.