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

  • Compatible Magnets

  • Available Equipment

  • Single axis rotator for angle dependent information
  • NHMFL Synchronous Lock-in Amplifier
  • Keithley Electrometers
  • Commercial lock-in amplifiers, eg. Stanford Research System, Signal
  • Wheatstone bridge circuit

Images & Sample Data

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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 

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Last modified on 29 September 2014