  We present the spin quantum Otto machine under different optimization
criterion when function either as a heat engine or a refrigerator. We examine
the optimal performance of the heat engine and refrigerator depending on their
efficiency, output power and maximum entropy production. For heat engine case,
we obtain the expression for the upper and lower bounds efficiencies at maximum
power and maximum ecological function. In addition, the spin quantum Otto
refrigerator coefficient of performance is optimized for three different
criterion -- cooling power, product of performance and power and ecological
function. We further study the dimensionless power loss to the cold reservoir
when the machine is operating as a heat engine as well as its counterpart for
the refrigerator case. We find that the maximum operation of the heat engine
(refrigerator) cycle is when optimized with respect to hot (cold) reservoir
frequency.
