Low temperature magnetic force microscope utilizing a piezoresistive cantilever

Abstract

We have developed a low temperature magnetic force microscope capable of operation down to 6 K in vacuum by using piezoresistive cantilevers. We use the non-contact frequency modulation technique to detect the magnetic force gradient between an iron-coated tip and the sample. We demonstrate the operation of this new instrument by obtaining images of magnetic domains in VHS tape at room temperature, 77 and 6 K. This microscope is ideally suited for the characterization of thin films of high temperature superconductors.

Strain-driven charge-ordered state inLa0.67Ca0.33MnO3

“…The low temperature MFM has been described in detail previously [7,8]. It is a frequency-modulated MFM that measures the magnetic force gradient F ′ (x,y) distribution on a sample.…”

“…The output of this feedback system is used to construct an image of constant force gradient. This low temperature MFM has been used to study a variety of materials [7][8][9][10][11].…”

Scanning Probe Microscopy and Spectroscopy of High Temperature Superconductors

“…Consequently a more forgiving technique for imaging superconductors was developed based on the magnetic force microscope [21,22]. The easiest way to understand why an MFM should be sensitive to superconductive properties is to remember the classic demonstration of a permanent magnet levitating above a high T, superconductor.…”

Design and construction of a heat stage for investigations of samples by atomic force microscopy above ambient temperatures

“…13,[19][20][21][22] The most direct solution to the problems involved in performing AFM microscopy above ambient temperatures is to change the ambient temperature ͑i.e., to place the microscope in an insulated box͒ and then operate the microscope at the desired temperature after thermal equilibrium has been established. This method has successfully been applied by several groups 19,20,22 to samples studied by AFM at temperatures from 6 K up to room temperature, but has so far been unsatisfactory when studying samples above room temperature. 5,20,23 Among other reasons, this may be due to the fact that the loading forces vary due to thermally induced cantilever drift.…”