Tuning of exchange bias with interfacial ferromagnetism in NdNiO 3 /NdMnO 3 heterostructures

Abstract

Two series of NdNiO 3 /NdMnO 3 heterostructures, S1 and S2, have been deposited respectively on [(LaAlO 3 ) 0.3 (Sr 2 AlTaO 6 ) 0.7 ] and SrTiO 3 single crystals (1 0 0) by pulsed laser deposition method. Here, the constituent materials are both antiferromagnetic at ground state. The number of layers n for each material has been varied from 1 to 4 in order to study the effects on the magnetic properties of these heterostructures. In spite of antiferromagnetic constituent materials, ferromagnetic interactions take place between Mn and Ni ions at the interface and caused magnetic hysteresis for all the heterostructures. In addition to the interfacial ferromagnetic interactions, a negative exchange bias is also realized in both the series. The largest exchange bias is observed at 25 K, which again enhances with an increase in n. The exchange bias decreases with increasing temperature and it vanishes above 90 K in both the series. In addition to exchange bias, a vertical shift in the magnetic hysteresis loop is observed, which varies depending on interfacial area in the heterostructures and the temperature. Our experimental results clearly demonstrate that the exchange bias and the vertical shift of magnetic hysteresis of these heterostructures can be tuned by interface engineering. © 2019 Elsevier B.V.