Current controlled negative differential resistance behavior in Co2FeO2BO3 and Fe3O2BO3 single crystals

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Writers: E.C. dos Santos; D.C. Freitas and I. Fier; J.C. Fernandes; M.A. Continentino; A.J.A. de Oliveira and L. Walmsley

Keywords: A. Ludwigites; D. NDR; D. Joule heating; D. Charge order depinning; D. Oscillations

Abstract: I–V curves showing negative differential resistance (NDR) are reported for single crystals of Co₂FeO₂BO₃ at 315 K and 290 K and for Fe₃O₂BO₃ at 300 K, 260 K and 220 K. Resistivity measurements are presented for both systems, parallel and perpendicular to the c axis, in the range 315–120 K. The high hysteretic behavior of the I–V curves in Co₂FeO₂BO₃ around room temperature is discussed and the heat dissipated is estimated, suggesting an increase in the sample temperature of almost 22 K for the I–V curve at 315 K and a dominant contribution of Joule self-heating for the observed NDR. In contrast, insignificant hysteresis is observed on the I–V curves of Fe₃O₂BO₃ around room temperature. The depinning of charge order domains is suggested as the main contribution to the NDR phenomenon for Fe₃O₂BO₃. The high reproducibility of the NDR in the Fe₃O₂BO₃ single crystal allows its use as a low frequency oscillator, as it is demonstrated.