Metglas - Magamp

High Frequency Square Loop Cores Technical Bulletin             
Square Loop Cores manufactured with cobalt-based METGLAS® amorphous alloy 2714A allow the design of mag amps that can operate at higher frequencies than previously possible. Their combination of magnetic properties enable magnetic amplifiers to provide unparalleled precision and efficiency in output regulation.

Mag amps are particularly well suited or outputs with currents of 1 amp to several ten of amps, although they are also used at lower currents where tight regulation and efficiency are extremely important.

Conventional regulated outputs are limited at higher frequencies and output currents. Linear regulators cannot handle output currents that exceed one or two amperes efficiently, and thus require heat sinking schemes, which increase the size of the power supply. Independent switched-mode sub-regulators avoid this inefficiency, but usually require circuitry which is more complex, expensive and less reliable than a mag amp.

Standard sizes are available from 9.6 mm to 34.1 mm OD and the possibility of manufacturing custom sizes also exists. Core coatings meeting UL94V-0 and temperature class F are available upon request.


METGLAS® Square Loops magnetic cores are specifically designed to exhibit an extremely square dc hysteresis loop and high BSAT resulting in the following important benefits:

  • Low saturated permeability
  • Low coercive field – indicating a small reset current
  • Low profile – enabling weight and volume reduction of up to 50 %
  • Low loss – resulting from micro-thin METGLAS® ribbon (18µm)

Physical Properties METGLAS® ALLOY 2741AF

Ribbon Thickness(µm): 18
Density (g/cm³): 7.59
Thermal Expansion (ppm/°C): 12.7
Crystallization Temperature (°C): 560
Curie Temperature (°C): 225
Continuous Service Temperature (°C): 90
Tensile Strengh (MN/m²): 1k-1.7k
Elastics Modulus (GN/m²): 100-110
Vicker´s Hardness (50g load): 960

Magnatic Properties METGLAS POWERLITE® Cores

Saturation Flux Density (Telsa): 0.57
Saturation Magnetostriction (ppm): <<1
Electrical Resistivity (µ-Ω-cm): 142
Squareness Ratio (%): >95

Square Loop Cores Standard Core Sizes
Square Loop Cores Standard Core Sizes