Marker for use in a magnetic anti-theft security system and method for marking the marker

A method for manufacturing an activation strip for a magnetic anti-theft security system, comprising the steps of:

• providing an alloy having a composition 8 to 25 wt % Ni, 1.5 to 4.5 wt % Al, 0.5 to 3 wt % Ti, and a remainder of iron;
• melting said alloy in an environment selected from the group consisting of a vacuum and a protective atmosphere to obtain a melted alloy, and casting said melted alloy into an ingot;
• hot working said ingot to form a ribbon at a temperature above approximately 800° C.;
• annealing said ribbon at a temperature above approximately 800° C.;
• rapidly cooling said ribbon to produce a cooled ribbon having a cross-section;
• cold-working said cooled ribbon and thereby reducing the cross-section thereof by approximately 90%, to obtain a cold-worked ribbon;
• annealing said cold-worked ribbon in a range between approximately 650° and 700° C. to obtain a cold-worked and annealed ribbon having a cross-section;
• cold-working said cold-worked and intermediately annealed ribbon to reduce the cross-section thereof by at least 60% to obtain a twice cold-worked ribbon;
• annealing said twice cold-worked ribbon at a temperature in a range between approximately 400° and 600° to obtain a finished ribbon;
• and
• cutting and trimming said finished ribbon into a plurality of activation strips, said activation strips having a coercive force Hc between and 10 and 24 A/cm and a remanence Br of at least 1.3 T.