  In the admixed Nd0.75Ho0.25Al2 system, magnetic moments of Nd and Ho
occupying the same crystallographic site are antiferromagnetically coupled and
the chosen stoichiometry displays a magnetic compensation behavior (Tcomp of
about 24 K) in all orientations. In the vicinity of Tcomp, the conduction
electron polarization (CEP) assumes the role of a soft ferromagnet exchange
coupled to a pseudo-antiferromagnet comprising Nd/Ho moments, resulting in an
asymmetry in the hysteretic (M-H) loop, i.e., the notion of an exchange bias
field (Hexch). Across Tcomp, the CEP contribution reverses sign, and in
consonance, the asymmetry in the M-H loop also undergoes a phase reversal.
Interestingly, the width of the M-H loop shows a divergence, followed by a
collapse on approaching Tcomp from either end. The observed behavior confirms a
long standing prediction based on a phenomenological model for ferrimagnetic
systems. The field induced changes across Tcomp leave an imprint of a
quasi-phase transition in the heat capacity data. Magneto-resistance (\Delta R
/ R vs T) has an oscillatory response, in which the changes across Tc and Tcomp
can be recognized.

Strongly Correlated Electrons;Materials Science