Torque Magnetometry in Pulsed Fields

The unloaded resonant frequency of 250-300kHz allows for fast response in pulsed magnetic fields (65T – 8ms rise time). A balanced Wheatstone bridge and ground shielding to prevent inductive/capacitive cross talk are used to detect a torque signal on the order of 10-13 Nm on sub-µg samples. The noise floor of a typical balanced bridge resistance measurement is less than 5mΩ/500Ω. The torque magnetometry technique has been successfully used to detect anisotropy changes in strongly correlated magnetic systems and resolve quantum oscillations for mapping out Fermi surface topology.

Instrumentation

Images & Sample Data

Click on an image for larger view and details.

• 50μm³ single crystal mounted on the tip of the cantilever. 50μm³ single crystal mounted on the tip of the cantilever.
• Rotator probe. Rotator probe.
• Angle dependent torque measurements done in the superconducting magnet. Angle dependent torque measurements done in the superconducting magnet.
• The angle dependence of quantum oscillations. The angle dependence of quantum oscillations.
• 50μm³ single crystal mounted on the tip of the cantilever. 50μm³ single crystal mounted on the tip of the cantilever.
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Related Publications

K.A. Modic, et al, Realization of a three-dimensional spin-anisotropic harmonic honeycomb iridate, Nat. Commun. 5:4203 doi: 10.1038/ncomms5203  (2014) Read online 

J.G. Analytis, et al, Quantum oscillations in the parent pnictide BaFe₂As₂: Itinerant electrons in the reconstructed state, Phys. Rev. B 103 (2009) Read online 

J.G. Analytis, et al, Fermi Surface of SrFe₂P₂ Determined by the de Haas–van Alphen Effect, Phys. Rev. B 103 (2009) Read online 

Amalia I. Coldea, et al, Topological Change of the Fermi Surface in Ternary Iron Pnictides with Reduced c/a Ratio: A de Haas–van Alphen Study of CaFe₂P₂, Phys. Rev. B 103 (2009) Read online 

Staff Contact

• Ross McDonald