The anisotropy and magnetostriction of single crystals of several ferromagnetic materials have been determined experimentally. The materials include the metals iron and nickel, binary alloys of nickel iron, silicon iron, aluminum iron, cobalt nickel, and cobalt iron, ternary alloys of molybdenum nickel iron, nickel cobalt iron, and molybdenum aluminum iron, and magnetite. The effect of the order-disorder reaction on these properties was measured for several of the alloys. The present data for the nickel iron and silicon iron systems agree well with recently published values. Ordering generally raises the magnetostriction and lowers the anisotropy of the aluminum iron alloys near the Fe3Al composition. The first anisotropy constant, K1, for the cobalt nickel system as derived from torque curves is similar to old data derived from magnetization curves. However, K1 for cobalt iron (30, 35, and 45% cobalt) appears to be considerably larger than previously reported. In general, the addition of cobalt to nickel and to iron changes the magnetostriction constants (λ100 and λ111) toward large positive values. Thus, λ100 increases to 100×10−6 for 50% cobalt nickel and to 130×10−6 for 45% cobalt iron; λ111 increases to 30×10−6 for 45% cobalt iron but remains approximately constant for the cobalt nickel alloys.

The magnetic anisotropy and magnetostriction of single crystals of alloys between 25 weight % and 59 weight % cobalt in iron have been determined in the disordered and ordered states. The magnetostrictionis large and positive for all alloys in both states of order (up to 150×10−6 for λ100 and 40×10−6 for λ111). The magnetic anisotropy becomes zero near 41% Co for the disordered state. Ordering shifts the zero-anisotropy composition to about 50% Co.

Single crystals of a number of binary iron-base alloys were grown, fabricated, and tested for magnetic anisotropy (K1) and magnetostriction (λ100 and λ111). The additions made to iron included vanadium, molybdenum, germanium, chromium, titanium, and tin. The anisotropy of iron was lowered by the addition elements with the possible exception of tin. On the other hand, λ100 of iron was generally raised by these addition elements. Only titanium and tin lowered λ100; however, titanium had limited solublilty in iron and tin caused embrittlement.