title: Flexible heat-flow sensing sheets based on the longitudinal spin Seebeck effect using one-dimensional spin-current conducting films.
abstract: Heat-flow sensing is expected to be an important technological component of smart thermal management in the future. Conventionally, the thermoelectric (TE) conversion technique, which is based on the Seebeck effect, has been used to measure a heat flow by converting the flow into electric voltage. However, for ubiquitous heat-flow visualization, thin and flexible sensors with extremely low thermal resistance are highly desired. Recently, another type of TE effect, the longitudinal spin Seebeck effect (LSSE), has aroused great interest because the LSSE potentially offers favourable features for TE applications such as simple thin-film device structures. Here we demonstrate an LSSE-based flexible TE sheet that is especially suitable for a heat-flow sensing application. This TE sheet contained a Ni0.2Zn0.3Fe2.5O4 film which was formed on a flexible plastic sheet using a spray-coating method known as "ferrite plating". The experimental results suggest that the ferrite-plated film, which has a columnar crystal structure aligned perpendicular to the film plane, functions as a unique one-dimensional spin-current conductor suitable for bendable LSSE-based sensors. This newly developed thin TE sheet may be attached to differently shaped heat sources without obstructing an innate heat flux, paving the way to versatile heat-flow measurements and management.
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.|Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai, 980-8577, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kirihara
authors.affiliation: NEC TOKIN Corporation, Sendai, 982-8510, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kondo
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.|Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai, 980-8577, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ishida
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.|Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai, 980-8577, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Ihara
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.
authors.forename: Yuma
authors.initials: Y
authors.lastname: Iwasaki
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.|Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai, 980-8577, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Someya
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.
authors.forename: Asuka
authors.initials: A
authors.lastname: Matsuba
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.|PRESTO, Japan Science and Technology Agency, Saitama, 332-0012, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Uchida
authors.affiliation: Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai, 980-8577, Japan.|Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.|WPI, Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.|Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, 319-1195, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Saitoh
authors.affiliation: NEC TOKIN Corporation, Sendai, 982-8510, Japan.
authors.forename: Naoharu
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kohmoto
authors.affiliation: Smart Energy Research Laboratories, NEC Corporation, Tsukuba, 305-8501, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Murakami