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Compositional Investigations on the Spin Thermoelectric Effect in Ta 100– x Cu x /Yttrium Iron Garnet Thin Films
Author(s) -
Yin Yig,
Tiwari Ashutosh
Publication year - 2021
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000464
Subject(s) - materials science , thermoelectric effect , yttrium iron garnet , electrical resistivity and conductivity , yttrium , electrode , sputtering , thin film , analytical chemistry (journal) , condensed matter physics , metallurgy , nanotechnology , electrical engineering , chemistry , oxide , physics , chromatography , thermodynamics , engineering
Herein, the performance of spin thermoelectric devices comprising Ta 100– x Cu x /yttrium iron garnet (YIG) films is investigated. Metallic electrodes of Ta 100– x Cu x ( x = 2, 3, 4, 5, and 7) are fabricated on high‐quality YIG films by magnetron sputtering technique. On each film, an undoped Ta electrode is also fabricated for the sake of precise comparison of spin thermoelectric performance. The hybrid Ta 100– x Cu x /YIG devices thus prepared are examined in a longitudinal geometry for the measurement of thermal voltages ( V t ). The experiments show that the voltages generated across the Ta 100– x Cu x films with x = 2, 3, and 4 are higher compared with the ones across pure Ta, whereas it is slightly lower for x = 7 film. Such improvement in V t is ascribed to an increase in the resistivity of Ta 100– x Cu x that strengthens the spin thermoelectric voltage. However, the surface of TaCu alloy films is observed to become rougher as the Cu ratio increases, which affects the injection of spin current across the interface. Due to the interplay between the resistivity and interfacial roughness of TaCu electrodes, the best thermoelectric response is obtained in the Ta 97 Cu 3 /YIG system, which is five times higher than the one obtained for undoped Ta/YIG.