  We report an experimental setup for simultaneously measuring specific heat
and thermal conductivity in feedback-controlled pulsed magnetic fields of 50
msec duration at cryogenic temperatures. A stabilized magnetic field pulse
obtained by the feedback control, which dramatically improves the thermal
stability of the setup and sample, is used in combination with the flash method
to obtain absolute values of thermal properties up to 37.2 T in the 2 K to 16 K
temperature range. We describe the experimental setup and demonstrate the
performance of the present method with measurements on single crystal samples
of the geometrically frustrated quantum spin-dimer system SrCu$_2$(BO$_3$)$_2$.
Our proof-of-principle results show excellent agreement with data taken using a
standard steady-state method, confirming the validity and convenience of the
present approach.
