thin films

We present a study of the physical properties of perovskite oxide Nd_0.5Sr_0.5MnO₃ (NSMO) thin films grown on (110)-oriented SrTiO₃ substrates. In bulk form, NSMO displays magnetic and electronic transitions from paramagnetic/insulator to ferromagnetic (FM)/metal and then to antiferromagnetic (AFM)/charge-ordered insulating phase with decreasing temperature. In thin films, AFM ordering only occurs in an anisotropic strain state such as those obtained in (110)-oriented substrates which allows for Jahn-Teller distortions of the MnO₆ octahedral and MnO₆ bond length distortions [1]. In this work, resonant x-ray reflectivity and magnetometry measurements showed that the NSMO film breaks up into three layers with different density and magnetic properties. X-ray magnetic circular dichroism confirmed the FM-AFM transition occurs between 80 K and 160 K for the main portion of the NSMO film, while x-ray magnetic linear dichroism provided a clear signature of the AFM phase at 80 K. At an intermediate temperature of 110 K, photoemission electron microscopy demonstrated the coexistence of FM and AFM domains. These temperature-dependent transitions have strong potential applications in next generation memory devices.

[1] S. Y. Jang et al., Solid State Commun., 149, 1760-1764 (2009)