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Title: Mode-hopping mechanism generating colored noise in a magnetic tunnel junction based spin torque oscillator

The frequency noise spectrum of a magnetic tunnel junction based spin torque oscillator is examined where multiple modes and mode-hopping events are observed. The frequency noise spectrum is found to consist of both white noise and 1/f frequency noise. We find a systematic and similar dependence of both white noise and 1/f frequency noise on bias current and the relative angle between the reference and free layers, which changes the effective damping and hence the mode-hopping behavior in this system. The frequency at which the 1/f frequency noise changes to white noise increases as the free layer is aligned away from the anti-parallel orientation w.r.t the reference layer. These results indicate that the origin of 1/f frequency noise is related to mode-hopping, which produces both white noise as well as 1/f frequency noise similar to the case of ring lasers.
Authors:
 [1] ; ;  [2] ;  [3] ;  [2] ;  [4] ;  [1] ;  [4]
  1. Department of Physics, Indian Institute of Technology, Delhi, New Delhi 110016 (India)
  2. Department of Physics, University of Gothenburg, Gothenburg 412 96 (Sweden)
  3. Argonne National Laboratory, Materials Science Division, Lemont, Illinois 60439 (United States)
  4. (Sweden)
Publication Date:
OSTI Identifier:
22350803
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COLOR; CURRENTS; DAMPING; NOISE; OSCILLATORS; RING LASERS; SEMICONDUCTOR JUNCTIONS; SPECTRA; SPIN; TORQUE; TUNNEL EFFECT