Odd-Parity Superconductivity with Parallel Spin Pairing in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>UPt</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>: Evidence from<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>195</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi>Pt</mml:mi></mml:math>Knight Shift Study

The temperature dependence of the ${}^{195}\mathrm{Pt}$ Knight shift, $K$, for the high quality single crystal ${\mathrm{UPt}}_{3}$ has been measured down to $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}28\mathrm{mK}$ in applied magnetic fields parallel and perpendicular to the hexagonal $c$ axis. No change of $K$'s has been found across the superconducting transition temperature ${T}_{c}$ down to 28 mK regardless of the crystal directions and independent of the superconducting multiphases. It is demonstrated that ${\mathrm{UPt}}_{3}$ is the odd-parity superconductor with parallel spin pairing following the direction of the magnetic field in a range of 4.4--15.6 kOe without an appreciable pinning of the order parameter to the lattice.