Role of spin mixing conductance in determining thermal spin pumping near the ferromagnetic phase transition in EuO_{1-x} and La2NiMnO6

Abstract

We present a comprehensive study of the temperature (T) dependence of the longitudinal spin Seebeck effect (LSSE) in Pt/EuO_{1-x} and Pt/La2NiMnO6 (LNMO) hybrid structures across their Curie temperatures (Tc). Both systems host ferromagnetic interaction below Tc, hence present optimal conditions for testing magnon spin current based theories against ferrimagnetic YIG. Notably, we observe an anomalous Nernst effect (ANE) generated voltage in bare EuO_{1-x}, however, we find LSSE predominates the thermal signals in the bilayers with Pt. The T-dependence of the LSSE in small T-range near Tc could be fitted to a power law of the form (Tc-T)^P. The derived critical exponent, P, was verified for different methods of LSSE representation and sample crystallinity. The results are explained based on the magnon-driven thermal spin pumping mechanism that relate the T-dependence of LSSE to the spin mixing conductance (Gmix) at the heavy metal/ferromagnet (HM/FM) interface, which in turn is known to vary in accordance with the square of the spontaneous magnetization (Ms). Additionally, the T-dependence of the real part of Gmix derived from spin Hall magnetoresistance measurements at different temperatures for the Pt/LNMO structure, further establish the interdependence.

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Cited by in corpus (8)

• Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids
• Mechanism of paramagnetic spin Seebeck effect
• Table-like magnetocaloric effect and enhanced refrigerant capacity in EuO1-δ thin films
• Measurement of the heat flux normalised spin Seebeck coefficient of thin films as a function of temperature
• Probing magnetic anisotropy and spin-reorientation transition in 3D antiferromagnet, Ho${}_{0.5}$Dy${}_{0.5}$FeO${}_3|$Pt using spin Hall magnetoresistance
• Robust electronic and tunable magnetic states in Sm${}_2$NiMnO${}_6$ ferromagnetic insulator
• Low temperature spin Seebeck effect in non-magnetic vanadium dioxide
• Spin Seebeck in the weak exchange coupled van der Waals antiferromagnet