title: Bolometer detection of magnetic resonances in nanoscaled objects.
abstract: We report on a nanoscaled thermocouple (ThC) as a temperature sensor of a highly sensitive bolometer for probing the dissipative damping of spin dynamics in nanosized Permalloy (Py) stripes. The Au-Pd ThC based device is fabricated by standard electron beam lithography on a 200 nm silicon nitride membrane to minimize heat dissipation through the substrate. We show that this thermal sensor allows not only measurements of the temperature change on the order of a few mK due to the uniform resonant microwave (MW) absorption by the Py stripe but also detection of standing spin waves of different mode numbers. Using a 3D finite element method, we estimate the absorbed MW power by the stripe in resonance and prove the necessity of using substrates with an extremely low heat dissipation like a silicon nitride membrane for successful thermal detection. The voltage responsivity and the noise equivalent power for the ThC-based bolometer are equal to 15 V W(-1) and 3 nW Hz(-1/2), respectively. The ThC device offers a magnetic resonance response of 1 nV/(μ(B) W) corresponding to a sensitivity of 10(9) spins and a temperature resolution of 300 μK under vacuum conditions.
authors.affiliation: Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, D-47057 Duisburg, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Rod
authors.forename: Ralf
authors.initials: R
authors.lastname: Meckenstock
authors.forename: Horst
authors.initials: H
authors.lastname: Zähres
authors.forename: Christian
authors.initials: C
authors.lastname: Derricks
authors.forename: Fedor
authors.initials: F
authors.lastname: Mushenok
authors.forename: Nathalie
authors.initials: N
authors.lastname: Reckers
authors.forename: Puchong
authors.initials: P
authors.lastname: Kijamnajsuk
authors.forename: Ulf
authors.initials: U
authors.lastname: Wiedwald
authors.forename: Michael
authors.initials: M
authors.lastname: Farle