Real-space magnetic imaging of the spinel MnV2O4

Wolin, Brian Augustus

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https://hdl.handle.net/2142/98089 Copy

Description

Title

Real-space magnetic imaging of the spinel MnV2O4

Author(s)

Wolin, Brian Augustus

Issue Date

2017-05-01

Director of Research (if dissertation) or Advisor (if thesis)

Budakian, Raffi

Doctoral Committee Chair(s)

Cooper, Lance

Committee Member(s)

• Martinez Outschoorn, Verena
• Clark, Bryan

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Spinel
• Spinels
• Multiferroic
• multiferroics
• multiferroism
• Magnetic force microscopy (MFM)
• MnV2O4
• Magnetic imaging
• Strain
• Quantitative magnetic force microscopy (MFM)

Abstract

Controlling multiferroic behavior in materials will enable the development of a wide variety of technological applications. However, the exact mechanisms by which multiferroic behavior arises in many materials are not well understood. One such class of materials are the spinels, including MnV2O4. Bulk probe studies of this compound have yielded conflicting and inconclusive results. To inform the debate and better understand the underlying physics, we performed magnetic force microscopy measurements on two MnV2O4 samples with differing degrees of mechanical strain. These local investigations revealed sub-um-scale patterns in the magnetic structure in both samples. In one case, the magnetization of these stripes is estimated at Mz ~ 10^5 A/m, which is on the order of previous saturation magnetization measurements. The discovery of such large inhomogeneities necessitates revision of theoretical proposals and reinterpretation of experimental data regarding the low-temperature phases of the spinels. Similar MFM measurements of a related material (Mn3O4) provide evidence that magnetic inhomogeneity is a common feature in the magnetically ordered phases of multiferroic spinel compounds.

Graduation Semester

2017-08

Type of Resource

text

Permalink

http://hdl.handle.net/2142/98089

Copyright and License Information

Copyright 2017 Brian Wolin

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