透磁合金 ，又称坡莫合金是镍铁的磁合金。通常指，20%铁和80%镍的合金。透磁合金有高磁导率，低矫顽力，接近0的磁力控制，和明显的各向异性的磁阻效应。当不定的压力在薄膜上很可能对电磁特性引起毁灭性的改变，其低磁力控制则在工业应用上具有决定性的意义。透磁合金的电阻率通常由于强度和所施加磁场的方向的因素，变化范围在5%以内。透磁合金具有典型的等轴晶系晶体结构，其晶格常量约为0.355nm，在临近镍80%集中的区域。

坡莫合金是一种在较弱磁场下有较高的磁导率的铁镍合金

Permalloy is a nickel–iron magnetic alloy, with about 80% nickel and 20% iron content. Invented in 1914 by physicist Gustav Elmen at Bell Telephone Laboratories, it is notable for its very high magnetic permeability, which makes it useful as a magnetic core material in electrical and electronic equipment, and also in magnetic shielding to block magnetic fields. Commercial permalloy alloys typically have relative permeability of around 100,000, compared to several thousand for ordinary steel.