Fieldlike and antidamping spin-orbit torques in as-grown and annealed Ta/CoFeB/MgO layers

We present a comprehensive study of the current-induced spin-orbit torques in perpendicularly magnetized Ta/CoFeB/MgO layers. The samples were annealed in steps up to 300 °C and characterized using x-ray-absorption spectroscopy, transmission electron microscopy, resistivity, and Hall effect measurem...

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Detalles Bibliográficos
Autores: Avci, Can Onur|||0000-0003-1226-2342, Garello, Kevin|||0000-0003-0236-322X, Nistor, Corneliu, Godey, Sylvie, Ballesteros, Belén|||0000-0002-1958-8911, Mugarza, Aitor|||0000-0002-2698-885X, Barla, Alessandro|||0000-0002-5632-4915, Valvidares, Manuel|||0000-0003-4895-8114, Pellegrin, Eric|||0000-0002-1648-0331, Ghosh, Abhijit, Miron, Ioan Mihai, Boulle, Olivier, Auffret, Stéphane, Gaudin, Gilles, Gambardella, Pietro|||0000-0003-0031-9217
Tipo de recurso: artículo
Fecha de publicación:2014
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:232132
Acceso en línea:https://ddd.uab.cat/record/232132
https://dx.doi.org/urn:doi:10.1103/PhysRevB.89.214419
Access Level:acceso abierto
Descripción
Sumario:We present a comprehensive study of the current-induced spin-orbit torques in perpendicularly magnetized Ta/CoFeB/MgO layers. The samples were annealed in steps up to 300 °C and characterized using x-ray-absorption spectroscopy, transmission electron microscopy, resistivity, and Hall effect measurements. By performing adiabatic harmonic Hall voltage measurements, we show that the transverse (fieldlike) and longitudinal (antidampinglike) spin-orbit torques are composed of constant and magnetization-dependent contributions, both of which vary strongly with annealing. Such variations correlate with changes of the saturation magnetization and magnetic anisotropy and are assigned to chemical and structural modifications of the layers. The relative variation of the constant and anisotropic torque terms as a function of annealing temperature is opposite for the fieldlike and antidamping torques. Measurements of the switching probability using sub-μs current pulses show that the critical current increases with the magnetic anisotropy of the layers, whereas the switching efficiency, measured as the ratio of magnetic anisotropy energy and pulse energy, decreases. The optimal annealing temperature to achieve maximum magnetic anisotropy, saturation magnetization, and switching efficiency is determined to be between 240 and 270°C.

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