Face-on orientation of spin ladders in La5Ca9Cu24O41 films deposited by radio-frequency magnetron sputtering on heated SiO2 and Si substrates

• Published in: Applied surface science Vol. 604; p. 154444
• Main Authors: Watanabe, Shota, Terakado, Nobuaki, Takahashi, Yoshihiro, Miyazaki, Takamichi, Naruse, Koki, Kawamata, Takayuki, Fujiwara, Takumi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2022
• Subjects: Dynamic control of heat flow; Frequency-domain thermoreflectance; Radio-frequency magnetron sputtering; Spin-ladder cuprate; Thermal management; Thermal management; Frequency-domain thermoreflectance; Radio-frequency magnetron sputtering; Dynamic control of heat flow; Spin-ladder cuprate
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.154444

[Display omitted] •We deposited La5Ca9Cu24O41 on heated substrates via rf sputtering.•The substrate heating led to a columnar structure and the b-axis orientation.•The columnar structure can be explained by the usual columnar growth model.•The Cu–O bonds forming the ca plane can be dominant for the b-axis orientation. Spin-ladder cuprates such as La5Ca9Cu24O41 are promising materials for advanced thermal management applications owing to their highly anisotropic and dynamically controllable thermal conductivity originating from spin ladders. Therefore, the orientation control of spin ladders is required in film fabrication methods that are extensively used in device engineering, such as sputtering. We found that La5Ca9Cu24O41 films with a columnar structure and the face-on orientation of spin ladders are formed on heated SiO2 (glass) and Si substrates via radio-frequency magnetron sputtering. The structural properties of the films were investigated, and the film formation mechanism was discussed. Our film fabrication method can pave the way for the development of new thermal management devices, such as active heat spreaders.