Spin-mediated dissipation and frequency shifts of a cantilever at milliKelvin temperatures

• Published in: arXiv.org
• Main Authors: A M J den Haan, Wagenaar, J J T, de Voogd, J M, Koning, G, Oosterkamp, T H
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 21.01.2016
• Subjects: Electron spin; Frequency shift; Physics - Mesoscale and Nanoscale Physics; Q factors; Relaxation time; Silicon
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1509.01251

We measure the dissipation and frequency shift of a magnetically coupled cantilever in the vicinity of a silicon chip, down to \(25\) mK. The dissipation and frequency shift originates from the interaction with the unpaired electrons, associated with the dangling bonds in the native oxide layer of the silicon, which form a two dimensional system of electron spins. We approach the sample with a \(3.43\) \(\mu\)m-diameter magnetic particle attached to an ultrasoft cantilever, and measure the frequency shift and quality factor as a function of temperature and the distance. Using a recent theoretical analysis [J. M. de Voogd et al., arXiv:1508.07972 (2015)] of the dynamics of a system consisting of a spin and a magnetic resonator, we are able to fit the data and extract the relaxation time \(T_1=0.39\pm0.08\) ms and spin density \(\sigma=0.14\pm0.01\) spins per nm\(^2\). Our analysis shows that at temperatures \(\leq500\) mK magnetic dissipation is an important source of non-contact friction.