High-strain, magnetic field-controlled actuator materials

An actuating element comprising:

• an actuator material which exhibits an austenitic crystal structure above a characteristic phase transformation temperature and which exhibits a martensitic twinned crystal structure below the phase transformation temperature, the actuator material being characterized as an alloy defined as (Ni.sub.a Fe.sub.b Co.sub.c).sub.65-x-y (Mn.sub.d Fe.sub.e Co.sub.f).sub.20+x (Ga.sub.g Si.sub.h Al.sub.i).sub.15+y, where x is between about 3 atomic % and about 15 atomic % and y is between about 3 atomic % and about 12 atomic %, and where a+b+c=1, where d+e+f=1, and g+h+i=1, and further being characterized by a magnetocrystalline anisotropy energy that is sufficient for enabling motion of twin boundaries of the martensitic twinned crystal structure in response to application of a magnetic field to the martensitic twinned crystal structure;
• and
• a magnetic actuation field source disposed with respect to the actuator material in an orientation that applies a magnetic actuation field to the actuator material in a direction that is substantially parallel with a plane bisecting an angle between easy axes of magnetization of two selected twin variants of the martensitic twinned crystal structure of the actuator material.

An actuating element comprising:

• an actuator material which exhibits an austenitic crystal structure above a characteristic phase transformation temperature and which exhibits a martensitic twinned crystal structure below the phase transformation temperature, the actuator material being characterized as an alloy defined as (Ni.sub.a Fe.sub.b Co.sub.c).sub.65-x-y (Mn.sub.d Fe.sub.e Co.sub.f).sub.20+x (Ga.sub.g Si.sub.h Al.sub.i).sub.15+y, where x is between about 3 atomic % and about 15 atomic % andy is between about 3 atomic % and about 12 atomic %, and where a+b+c=1, where d+e+f=1, and g+h+i=1, and further being characterized by a magnetocrystalline anisotropy energy that is sufficient for enabling motion of twin boundaries of the martensitic twinned crystal structure in response to application of a magnetic field to the martensitic twinned crystal structure;
• and
• a magnetic bias field source disposed with respect to the actuator material in an orientation that applies a magnetic bias field to the actuator material, and a magnetic actuation field source disposed with respect to the actuator material in an orientation that applies a magnetic actuation field to the actuator material in a direction that is substantially perpendicular to the orientation of the applied magnetic bias field.

An actuating element comprising:

• an actuator material which exhibits an austenitic crystal structure above a characteristic phase transformation temperature and which exhibits a martensitic twinned crystal structure below the phase transformation temperature, the actuator material being characterized by a magnetocrystalline anisotropy energy that is sufficient for enabling motion of twin boundaries of the martensitic twinned crystal structure in response to application of a magnetic field to the martensitic twinned crystal structure;
• and
• a magnetic actuation field source disposed with respect to the actuator material in an orientation that applies to the actuator material a magnetic actuation field in a direction that is substantially parallel with a selected twin boundary direction of the martensitic twinned crystal structure of the actuator material.

An actuating element comprising:

• an actuator material which exhibits an austenitic crystal structure above a characteristic phase transformation temperature and which exhibits a martensitic twinned crystal structure below the phase transformation temperature, the actuator material being characterized by a magnetocrystalline anisotropy energy that is sufficient for enabling motion of twin boundaries of the martensitic twinned crystal structure in response to application of a magnetic field to the martensitic twinned crystal structure;
• and
• a magnetic actuation field source disposed with respect to the actuator material in an orientation that applies to the actuator material a magnetic actuation field in a direction that is substantially parallel with a plane bisecting an angle between easy axes of magnetization of two selected twin variants of the martensitic twinned crystal structure of the actuator material.

An actuating element comprising:

• an actuator material which exhibits an austenitic crystal structure above a characteristic phase transformation temperature and which exhibits a martensitic twinned crystal structure below the phase transformation temperature, the actuator material being characterized by a magnetocrystalline anisotropy energy that is sufficient for enabling motion of twin boundaries of the martensitic twinned crystal structure in response to application of a magnetic field to the martensitic twinned crystal structure;
• and
• a magnetic bias field source disposed with respect to the actuator material in an orientation that applies a magnetic bias field to the actuator material, and a magnetic actuation field source disposed with respect to the actuator material in an orientation that applies a magnetic actuation field to the actuator material in a direction that is substantially perpendicular to the orientation of the applied magnetic bias field.