Probing Magnetic Transitions using Pure Spin Current

Danru Qu^1,5*, Po-Hsun Wu², Yen-Chang Tu², Yi-Hui Zhang², Tsao-Chi Chuang², Yin-Ze Lin², H. -L. Liang², S. F. Lee³, C. L. Chien⁴, Ssu-Yen Huang^2,5

¹Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
²Department of Physics, National Taiwan University, Taipei, Taiwan
³Institute of Physics, Academia Sinica, Taipei, Taiwan
⁴Department of Physics and Astronomy, Johns Hopkins University, Baltimore, USA
⁵Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, Taiwan

* Presenter:Danru Qu, email:danru@ntu.edu.tw

Pure spin current delivers the maximum angular momentum with the minimum Joule heat. With less power consumption, pure spin current can be much more energy efficient for device applications. In this talk, I will discuss the detection of magnetic transitions using pure spin current in various magnetic systems of interest. These include probing the spin freezing transition in the spin glass CuMn alloys [1], probing the spin fluctuation in ferromagnetic NiCu alloy [2], and probing the spin-flop transition in the antiferromagnetic insulator Cr₂O₃ [3]. In these works, we discover that the spin-to-charge conversions can be significantly enhanced at the magnetic phase transition temperatures [1, 2], which further results in a large spin Hall angle of about 46% in the Ni₈₀Cu₂₀ alloy [2]. We also demonstrate the electrical detection of the Néel vector rotation in Cr₂O₃ via the spin current probe and further arbitrarily manipulate the Néel vector using a magnetic field component in the hard-axis plane with a magnitude of about 1000 Oe [3]. Our works show the versatility of the pure spin current.

[1] P.-H. Wu, Y.-C. Tu, D. Qu*, H.-L. Liang, S.-F. Lee, and S.-Y. Huang*, Phys. Rev. B 101, 104413 (2020)
[2] P.-H. Wu, D. Qu*, Y.-C. Tu, Y.-Z. Lin, C. L. Chien*, and S.-Y. Huang*, Phys. Rev. Lett. 128, 227203 (2022)
[23] Y.-H. Zhang, T.-C. Chuang, D. Qu*, and S. Y. Huang*, Phys. Rev. B 105, 094442 (2022)

Keywords: pure spin current, spin Hall effect, spin fluctuation, spin-flop transition, spin Seebeck effect