Electrical low frequency random telegraph noise in magnetic tunnel junctions

Low frequency random telegraph noise (RTN) of electrical origin is reported in magnetic tunnel junction heads with ultrathin tunnel barriers (< 1 nm). The RTN is characterized by abrupt and randomly stepped voltage spikes which modulates 1/f noise property in frequency domain. The appearance of electrical RTN is restricted to limited ranges of bias voltage and temperature. Dependence of RTN statistics on temperature suggests that the dynamic resistance fluctuations could be generally described by a thermal activation model. The extracted activation energy, E-A, is found to be 0.3 x 10(-19) J, which is much smaller than reported activation energies for magnetic RTN in early giant magnetoresistive heads. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3070619]