Gradiometric micro-SQUID susceptometer for scanning measurements of mesoscopic samples

被引：141

作者：

Huber, Martin E. ^{[1
]}

Koshnick, Nicholas C. ^{[2
]}

Bluhm, Hendrik ^{[2
,3
]}

Archuleta, Leonard J. ^{[1
]}

Azua, Tommy ^{[1
]}

Bjornsson, Per G. ^{[2
]}

Gardner, Brian W. ^{[2
]}

Halloran, Sean T. ^{[1
]}

Lucero, Erik A. ^{[1
,4
]}

Moler, Kathryn A. ^{[2
]}

机构：

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

[2] Stanford Univ, Geballe Lab Adv Mat, Stanford, CA 94305 USA

[3] Harvard Univ, Dept Phys, Cambridge, MA 02138 USA

[4] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA

来源：

REVIEW OF SCIENTIFIC INSTRUMENTS | 2008年 / 79卷 / 05期

基金：

美国国家科学基金会;

关键词：

D O I：

10.1063/1.2932341

中图分类号：

TH7 [仪器、仪表];

学科分类号：

0804 ; 080401 ; 081102 ;

摘要：

We have fabricated and characterized micro-SQUID susceptometers for use in low-temperature scanning probe microscopy systems. The design features the following: a 4.6 mu m diameter pickup loop; an integrated field coil to apply a local field to the sample; an additional counterwound pickup-loop/field-coil pair to cancel the background signal from the applied field in the absence of the sample; modulation coils to allow setting the SQUID at its optimum bias point (independent of the applied field), and shielding and symmetry that minimizes coupling of magnetic fields into the leads and body of the SQUID. We use a SQUID series array preamplifier to obtain a system bandwidth of 1 MHz. The flux noise at 125 mK is approximately 0.25 mu Phi(0)/root Hz above 10 kHz, with a value of 2.5 mu Phi(0)/root Hz at 10 Hz. The nominal sensitivity to electron spins located at the center of the pickup loop is approximately 200 mu(B)/root Hz above 10 kHz, in the white-noise frequency region. (c) 2008 American Institute of Physics.

引用

页数：7

共 28 条

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[Anonymous], 2003, SQUID HDB

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BLUHM H, ARXIVCONDMAT07091175

[3]

BLUHM H, UNPUB

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