BARC/PUB/2020/0957

 
 

Interface-Induced Magnetization and Exchange Bias in LSMO/BFO Multiferroic Heterostructures

 
     
 
Author(s)

Prajapat, C. L.; Bhatt, H.; Yogesh Kumar; Rao, T. V. C.; Mishra, P. K.; Ravikumar, G.; and others
(TPD;SIRD;SSPD)

Source

ACS Applied Electronic Materials, 2020. Vol. 2: pp. 2629-2637

ABSTRACT

Interface-induced magnetization in BiFeO3 (BFO) at the La0.67Sr0.33MnO3 (LSMO)/BFO interface is an important factor in determining the magnetoelectric coupling, exchange bias, and other phenomena in LSMO/ BFO heterostructures. Using spin-dependent polarized neutron reflectivity (PNR), we report experimental evidence for the existence of a ferromagnetic (FM) interfacial BFO layer of a relatively large thickness of ∼8−15 unit cells (u.c.) at the LSMO/BFO interface. The interfacial FM BFO layer in different LSMO/BFO heterostructures is coupled both FM and antiferromagnetically (AFM), with the FM LSMO layer at the LSMO/BFO interface. We find an enhanced magnetization of 165 emu/cc (FM coupled) to −135 emu/cc (AFM coupled) for the interfacial BFO layer. We also observed an exchange bias in LSMO/BFO heterostructures, which was independently confirmed using PNR measurements by investigating the magnetization of the system under field cooling in a magnetic field of ±500 Oe. Our results further suggest that while interface roughness favors the formation of an interfacial ferromagnetic BFO layer with a higher thickness and order temperature, strain plays an important role in increasing the exchange bias blocking temperature in the LSMO/BFO heterostructure.

 
 
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