Microwave Surface Impedance and Nonlinear Properties of MgB2 Films
James Booth, Sang Y. Lee, Kenneth Leong, J. H. Lee, J. Lim, H. N. Lee, S. H. Moon, B. Oh
We have measured the temperature dependence of the microwave surface impedance and the nonlinear response of high-quality MgB2 films on c-cut sapphire at temperatures below 40 K. MgB2 films with surface resistance (Rs) as low as 0.09 mOhm} at 8 K and 19.6 GHz were prepared in an ex-situ process by annealing a boron layer in magnesium-rich environment. The nonlinear properties of the MgB2 films were investigated as a function of temperature by means of higher order harmonic generation measurements in patterned coplanar waveguide devices. The effects of surface ion-milling on the nonlinear properties of MgB2 films were also studied, and the nonlinear response of MgB2 films was compared with that of epitaxially grown YBCO films. The consequences of these measurements for passive microwave device applications of MgB2 films are also discussed.
, Lee, S.
, Leong, K.
, Lee, J.
, Lim, J.
, Lee, H.
, Moon, S.
and Oh, B.
Microwave Surface Impedance and Nonlinear Properties of MgB<sub>2</sub> Films, IEEE Transactions on Applied Superconductivity
(Accessed November 30, 2023)