= Solution
A bulk <ferromagnet> generally separates into <magnetic domains>. Within each domain many moments align and the local <magnetization> can be large, but different domain orientations partially or almost completely cancel the vector sum measured for the entire specimen. This reduces its external stray field and magnetostatic <energy>. Formation of <magnetic domain walls> costs exchange and anisotropy <energy>, so the actual pattern balances these costs with the reduction in stray-field <energy>.
A strong applied field can move domain walls and rotate moments toward a nearly <saturation magnetization>. When the field is removed, pinning and the sample's magnetic history determine the remanent moment. Thus a small net moment does not show that local ferromagnetic order has disappeared, or that moments within each domain are all randomly oriented. At finite <temperature>, thermal <spin> fluctuations also reduce the local ordered moment below its zero-temperature maximum even in a single-domain specimen. These two reductions—between-domain cancellation and within-domain thermal reduction—should be distinguished.
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