Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 23: Spincaloric Transport I (jointly with TT)
MA 23.3: Talk
Wednesday, March 18, 2015, 10:00–10:15, H 0110
How to control and determine the direction of thermal gradients in spin caloric measurements? — •Timo Kuschel, Tristan Matalla-Wagner, Michel Bovender, Oliver Reimer, Daniel Meier, Jan-Michael Schmalhorst und Günter Reiss — CSMD, Physics Department, Bielefeld University, Germany
In longitudinal spin Seebeck effect (LSSE) measurements in magnetic insulators like NiFe2O4 or Y3Fe5O12 with an out-of-plane thermal gradient ∇ T additional magnetic proximity effects in the adjacent spin detector material (e.g. Pt) have to be taken into account and can be identified or excluded by e.g. x-ray resonant magnetic reflectivity [1]. In transverse SSE experiments with in-plane ∇ T unintended out-of-plane ∇ T can induce additional contributions as mainly Nernst effects in magnetic metals [2] and primarily LSSE in magnetic insulators [3]. Therefore, the control and the determination of thermal gradient directions in spin Seebeck experiments should be investigated in detail.
Here, we present a new spin caloric setup which allows the rotation of in-plane thermal gradients based on the vectorial superposition of ∇x T and ∇y T. We check the in-plane direction of ∇ T by an infrared camera and will use the setup to study established and new spin caloric effects for different ∇ T directions. We further show exemplarily that linear and quadratic Nernst effects in CoFeTb thin films can be used to estimate the effective direction of ∇ T in all three spatial directions.
[1] T. Kuschel et al., submitted 2014, arxiv: 1411.0113
[2] D. Meier et al., Phys. Rev. B 88, 184425 (2013)
[3] D. Meier et al., submitted 2014, arxiv: 1411.6790