Search query: Observation of the spin  effect

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abstract: Reducing the heat generated in traditional electronics is a chief motivation for the development of spin based electronics, called spintronics. Spin based transistors that do not strictly rely on the raising or lowering of electrostatic barriers can overcome scaling limits in charge based transistors. Spin transport in semiconductors might also lead to dissipation less information transfer with pure spin currents. Despite these thermodynamic advantages, little experimental literature exists on the thermal aspects of spin transport in solids. A recent and surprising exception was the discovery of the spin Seebeck effect, reported as a measurement of a redistribution of spins along the length of a sample of permalloy (NiFe) induced by a temperature gradient. This macroscopic spatial distribution of spins is, surprisingly, many orders of magnitude larger than the spin diffusion length, which has generated strong interest in the thermal aspects of spin transport. Here, the spin Seebeck effect is observed in a ferromagnetic semiconductor, GaMnAs, which allows flexible design of the magnetization directions, a larger spin polarization, and measurements across the magnetic phase transition. This effect is observed even in the absence of longitudinal charge transport. The spatial distribution of spin currents is maintained across electrical breaks, highlighting the local nature of this thermally driven effect.
author_names: Christopher M Jaworski

Jianbo Yang

Shawn Mack

David D Awschalom

Joseph P Heremans

Robert C Myers
title: Observation of the spin Seebeck effect in a ferromagnetic semiconductor.
venue: Nature materials
year: 2010

abstract: The generation of electric voltage by placing a conductor in a temperature gradient is called the Seebeck effect. Its efficiency is represented by the Seebeck coefficient, S, which is defined as the ratio of the generated electric voltage to the temperature difference, and is determined by the scattering rate and the density of the conduction electrons. The effect can be exploited, for example, in thermal electric power generators and for temperature sensing, by connecting two conductors with different Seebeck coefficients, a device called a thermocouple. Here we report the observation of the thermal generation of driving power, or voltage, for electron spin: the spin Seebeck effect. Using a recently developed spin detection technique that involves the spin Hall effect, we measure the spin voltage generated from a temperature gradient in a metallic magnet. This thermally induced spin voltage persists even at distances far from the sample ends, and spins can be extracted from every position on the magnet simply by attaching a metal. The spin Seebeck effect observed here is directly applicable to the production of spin voltage generators, which are crucial for driving spintronic devices. The spin Seebeck effect allows us to pass a pure spin current, a flow of electron spins without electric currents, over a long distance. These innovative capabilities will invigorate spintronics research.
author_names: Kazuhito Uchida

S Takahashi

Kazuya Harii

Jun'ichi Ieda

Wataru Koshibae

Kazuya Ando

Sadamichi Maekawa

Eiji Saitoh
title: Observation of the spin Seebeck effect
venue: Nature
year: 2008

abstract: We report the experimental observation of the spin Seebeck effect in magnetite thin films. The signal observed at temperatures above the Verwey transition is a contribution from both the anomalous Nernst (ANE) and spin Seebeck (SSE) effects. The contribution from the ANE of the Fe3O4 layer to the SSE is found to be negligible due to the resistivity difference between Fe3O4 and Pt layers. Below the Verwey transition, the SSE is free from the ANE of the ferromagnetic layer and it is also found to dominate over the ANE due to magnetic proximity effect on the Pt layer.
author_names: Rafael Ramos

Takashi Kikkawa

Kazuhito Uchida

Hiroto Adachi

Irene Lucas

Myriam H Aguirre

Pedro Antonio Algarabel

Luis Morellon

Sadamichi Maekawa

Eiji Saitoh

Manuel Ricardo Ibarra
title: Observation of the spin Seebeck effect in epitaxial Fe3O4 thin films
year: 2013

abstract: We have developed a vectorial type of measurement for the spin Seebeck effect (SSE) in epitaxial NiFe$_2$O$_4$ thin films which have been grown by pulsed laser deposition on MgGa$_2$O$_4$ (MGO) with (001) and (011) orientation as well as CoGa$_2$O$_4$ (011) (CGO) thus varying the lattice mismatch. We confirm that a large lattice mismatch leads to strain anisotropy in addition to the magnetocrystalline anisotropy in the thin films using vibrating sample magnetometry and ferromagnetic resonance measurements. Moreover, we show that the existence of a magnetic strain anisotropy in NiFe$_2$O$_4$ thin films significantly impacts the shape and magnitude of the magnetic field dependent SSE voltage loops. We further demonstrate that bidirectional field dependent SSE voltage curves can be utilized to reveal the complete magnetization reversal process, which establishes a new vectorial magnetometry technique based on a spin caloric effect.
author_names: Zhong Li

Jan Krieft

Amit Vikram Singh

Sudhir Regmi

Ankur Rastogi

Abhishek Srivastava

Zbigniew Galazka

Tim Mewes

Arunava Gupta

Timo Kuschel
title: Vectorial observation of the spin Seebeck effect in epitaxial NiFe2O4 thin films with various magnetic anisotropy contributions
venue: Applied Physics Letters
year: 2019

author_names: Ken-ichi Uchida

Saburo Takahashi

Kazuya Harii

Jun'ichi Ieda

Wataru Koshibae

Kazuya Ando

Sadamichi Maekawa

Eiji Saitoh
title: Observation of the Spin Seebeck Effect.
year: 2009

author_names: I S Yoon

Sangeun Cho

Sh U Yuldashev
title: Observation of the Spin Seebeck Effect in Bi 2 Te 3 Topological Insulator without an External Magnetic Field
year: 2020

author_names: Sergio M Rezende

Jose Holanda

O Alves Santos

J B S Mendes

Matheus Gomes

R O Cunha

R L Rodriguez-Suarez

Antonio Azevedo
title: Spin current transport in an insulating antiferromagnet makes possible the observation of the spin Seebeck effect in permalloy separated from the anomalous Nernst effect
year: 2018

abstract: Understanding the transfer of spin angular momentum is essential in modern magnetism research. A model case is the generation of magnons in magnetic insulators by heating an adjacent metal film. Here, we reveal the initial steps of this spin Seebeck effect with <27 fs time resolution using terahertz spectroscopy on bilayers of ferrimagnetic yttrium iron garnet and platinum. Upon exciting the metal with an infrared laser pulse, a spin Seebeck current js arises on the same ~100 fs time scale on which the metal electrons thermalize. This observation highlights that efficient spin transfer critically relies on carrier multiplication and is driven by conduction electrons scattering off the metal insulator interface. Analytical modeling shows that the electrons' dynamics are almost instantaneously imprinted onto js because their spins have a correlation time of only ~4 fs and deflect the ferrimagnetic moments without inertia. Applications in material characterization, interface probing, spin noise spectroscopy and terahertz spin pumping emerge.Probing spin pumping in the terahertz regime allows one to reveal its initial elementary steps. Here, the authors show that the formation of the spin Seebeck current in YIG/Pt critically relies on hot thermalized metal electrons because they impinge on the metal insulator interface with maximum noise.
author_names: Tom S Seifert

Samridh Jaiswal

Joseph Barker

Sebastian T Weber

Ilya Razdolski

Joel Cramer

Oliver Gueckstock

Sebastian F Maehrlein

Lukas Nadvornik

Shun Watanabe

Chiara Ciccarelli

Alexey A Melnikov

Gerhard Jakob

Markus Munzenberg

Sebastian T B Goennenwein

Georg Woltersdorf

Baerbel Rethfeld

Piet W Brouwer

Martin Wolf

Mathias Klaui

Tobias Kampfrath
title: Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy
venue: Nature Communications
year: 2018

abstract: Abstract Rhodium (Rh) is a 4d metal possessing a large spin orbit coupling strength and spin Hall conductivity with a very small magnetic susceptibility, implying an insignificant magnetic proximity effect (MPE) We report here the observation of longitudinal spin Seebeck effect (LSSE) using Rh as a normal metal. A Rh film was sputtered on nanometer thick YIG films of highly crystalline nature and extremely low magnetic damping to obtain Rh/YIG hybrid structure. A clear thermal voltage Vth (SSE voltage) was obtained when a temperature gradient was applied on the Rh/YIG hybrid. The Rh film showed a very weak anomalous Hall resistance and the magneto resistive testing clearly ruled out the magnetization of the Rh films via MPE. The anisotropic magnetoresistance (AMR) revealed a clear spin hall magnetoresistance (SMR) signal in Rh film implying a purely intrinsic spin current generation, free from any parasitic magnetic effects. The work can open a new window in the study of pure and uncontaminated spin current, generated in ferromagnetic insulators, using Rh as spin current detector.
author_names: Fida Mohmed

Yuanhua Lin
title: The observation of inherent spin Seebeck effect in Rh/YIG hybrid structure
venue: Current Applied Physics
year: 2019

abstract: Abstract We report on the observation of the spin Seebeck effect in Ni Zn ferrites slabs with different Zn concentration. All samples have a spinel structure confirmed by XRD and TEM. We fully characterize the magnetic properties by VSM and Mossbauer spectroscopy. Samples exhibit a nonmonotonic magnetization behavior depending on the structural inversion parameter, however we found a spin Seebeck response voltage of about 25.5 nV/K independent of the magnetization and the inversion degree.
author_names: J D Arboleda

O Arnache

Myriam H Aguirre

Rafael Ramos

Alberto Anadon

Manuel Ricardo Ibarra
title: Evidence of the spin Seebeck effect in Ni Zn ferrites polycrystalline slabs
year: 2018