Spinlike Susceptibility of Metallic and Insulating Thin Films at Low Temperature

被引：57

作者：

Bluhm, Hendrik ^{[1
,2
]}

Bert, Julie A. ^{[1
,2
]}

Koshnick, Nicholas C. ^{[1
,2
]}

Huber, Martin E. ^{[3
,4
]}

Moler, Kathryn A. ^{[1
,2
]}

机构：

[1] Stanford Univ, Dept Phys, Stanford, CA 94305 USA

[2] Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA

[3] Univ Colorado, Dept Phys, Denver, CO 80217 USA

[4] Univ Colorado, Dept Elect Engn, Denver, CO 80217 USA

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 103卷 / 02期

基金：

美国国家科学基金会;

关键词：

NOISE;

D O I：

10.1103/PhysRevLett.103.026805

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Susceptibility measurements of patterned thin films at sub-K temperatures were carried out using a scanning SQUID microscope that can resolve signals corresponding to a few hundred Bohr magnetons. Several metallic and insulating thin films, even oxide-free Au films, show a paramagnetic response with a temperature dependence that indicates unpaired spins as the origin. The observed response exhibits a measurable out-of-phase component, which implies that these spins will create 1/f-like magnetic noise. The measured spin density is consistent with recent explanations of low frequency flux noise in SQUIDs and superconducting qubits in terms of spin fluctuations, and suggests that such unexpected spins may be even more ubiquitous than already indicated by earlier measurements. Our measurements set several constraints on the nature of these spins.

引用

页数：4

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