  Temperature in thermodynamics is synonymous with disorder, and responsible
for ultimately destroying ordered phases. Here, we show an unusual magnetic
transition where, with increasing the temperature of elemental neodymium,
long-range multi-Q magnetic order emerges from a self-induced spin glass. Using
temperature-dependent spin-polarized scanning tunneling microscopy, we
characterize the local Q order in the spin-Q glass phase and quantify the
emergence of long-range multi-Q order with increasing temperature. We develop
two distinct analysis tools, which enable the quantification of the glass
transition temperature, based on measured spatially-dependent magnetization. We
compare these observations with atomic spin dynamics simulations, which
reproduce the qualitative observation of a phase transition from a
low-temperature spin glass phase to an intermediate ordered multi-Q phase.
These simulations trace the origin of the unexpected high temperature order in
weakened frustration driven by temperature-dependent sublattice correlations.
These findings constitute an example of order from disorder and provide a rich
platform to study magnetization dynamics in a self-induced spin glass.
