NiO buffer layers were formed on a tape of Ni for making YBCO coated conductor by surface-oxidation epitaxy （SOE） process. Different oxidizing conditions such as temperature and duration were studied for Ni tapes. I...NiO buffer layers were formed on a tape of Ni for making YBCO coated conductor by surface-oxidation epitaxy （SOE） process. Different oxidizing conditions such as temperature and duration were studied for Ni tapes. It is found that the texture of NiO could be affected directly by the orientation and surface of substrate. X-ray diffraction （XRD） 2-2θ scan, φ-scan, and pole figure were employed to characterize the in-plane alignment and cube texture. X-ray φ-scan shows that NiO film is formed on Ni tape with high cube texture and a typical value at the full width at half maximum （FWHM） is ≤ 7.5°. Scanning electron microscopy was used to study the surface morphology of NiO films. No crack is found and the films appear dense. Such technique is simple and of low cost with perfect reproducibility, promising for developing long tapes.展开更多
Exchange bias,which typically requires a coupled ferromagnetic and antiferromagnetic interface,plays a key role in enhancing data storage technologies by reducing noise and improving signal readability.In this study,w...Exchange bias,which typically requires a coupled ferromagnetic and antiferromagnetic interface,plays a key role in enhancing data storage technologies by reducing noise and improving signal readability.In this study,we investigate the exchange bias phenomenon in surface-oxidized van der Waals material Fe_(3)GaTe_(2),which exhibits a blocking temperature of approximately 280 K—near room temperature.This behavior is particularly significant,as achieving room-temperature exchange bias has been challenging,potentially due to the lack of high-Néel-temperature van der Waals antiferromagnetic materials.Using ab initio calculations and magneto-optical methods,we propose a model to explain the origin of the exchange bias,thereby circumventing the need for complex fabrication typically required in transport measurements.Our findings suggest that surface oxidation plays a crucial role in realizing exchange bias behavior,which is strongly dependent on temperature,interfacial spin-pinning states,and the interplay between ferromagnetic and antiferromagnetic interactions.We also examine the stability and uniformity of this behavior in flakes of various thicknesses.These insights provide valuable understanding of near-room-temperature exchange bias in van der Waals materials,opening up possibilities for their integration into next-generation spintronic and data storage applications.展开更多
基金Project supported by National 863 Programof Ministry of Science and Technology of China (2002AA306211 ,2004AA306130)
文摘NiO buffer layers were formed on a tape of Ni for making YBCO coated conductor by surface-oxidation epitaxy （SOE） process. Different oxidizing conditions such as temperature and duration were studied for Ni tapes. It is found that the texture of NiO could be affected directly by the orientation and surface of substrate. X-ray diffraction （XRD） 2-2θ scan, φ-scan, and pole figure were employed to characterize the in-plane alignment and cube texture. X-ray φ-scan shows that NiO film is formed on Ni tape with high cube texture and a typical value at the full width at half maximum （FWHM） is ≤ 7.5°. Scanning electron microscopy was used to study the surface morphology of NiO films. No crack is found and the films appear dense. Such technique is simple and of low cost with perfect reproducibility, promising for developing long tapes.
基金support from the National Key Research and Development Program of China(No.2020YFA0309300)the National Natural Science Foundation of China(No.12241403)+1 种基金Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515140171 and 2024A1515011638)the Guangdong Program(No.2019QN01X113).
文摘Exchange bias,which typically requires a coupled ferromagnetic and antiferromagnetic interface,plays a key role in enhancing data storage technologies by reducing noise and improving signal readability.In this study,we investigate the exchange bias phenomenon in surface-oxidized van der Waals material Fe_(3)GaTe_(2),which exhibits a blocking temperature of approximately 280 K—near room temperature.This behavior is particularly significant,as achieving room-temperature exchange bias has been challenging,potentially due to the lack of high-Néel-temperature van der Waals antiferromagnetic materials.Using ab initio calculations and magneto-optical methods,we propose a model to explain the origin of the exchange bias,thereby circumventing the need for complex fabrication typically required in transport measurements.Our findings suggest that surface oxidation plays a crucial role in realizing exchange bias behavior,which is strongly dependent on temperature,interfacial spin-pinning states,and the interplay between ferromagnetic and antiferromagnetic interactions.We also examine the stability and uniformity of this behavior in flakes of various thicknesses.These insights provide valuable understanding of near-room-temperature exchange bias in van der Waals materials,opening up possibilities for their integration into next-generation spintronic and data storage applications.
