Multi-Axis Magnet systems for Vector Fields (MAxes
significant progress in technologies that allow sample manipulation at atomic level, however at sub Kelvin
temperatures, there is limited thermal budget and hence it’s preferable to rotate the magnetic field than
rotating the sample. Additional constraints come into play when systems are cooled using closed cycle
coolers as thermal budget is further restricted. Some of these requirements have pushed advancements in
areas of Multi-axis magnets, as using these it is possible to align samples in magnetic field to an accuracy
of better than 0.01 degrees.
A typical MAxesTM magnet is comprised of two or three independently controlled coil sets. A solenoid
coil produces the highest field along one axis. One or two sets of split coils produce fields along the
other 2 axes. By correctly energizing the coils with programmed coil constant a combined vector field
can be produced in a given direction of a known magnitude. This allows users to electronically
manipulate the field relative to the sample without the use of complex sample rotation equipment or
physically rotating the magnet position. Coil configurations could be with the split coils surrounding the
solenoid or the split coils nested inside the bore of a large solenoid. Typical specifications include high
field up to 9 Tesla (T) for the principal axis, having 2.0/3.0 inch vertical clear bore and 1T or 2T rotating
vector using any combination of x, y and z-axis magnets. Users needing higher vector field typically opt
for 2-axis systems.
The following table gives a snap shot sample of the capabilities of our MAxesTM systems.
Bore size MX-2 (YZ) 2D Vector field MX-3 (XYZ) 3D Vector field
2.0"
2.5"
3.0"
4.5T/9T 4.5T 1T/1T/12T 1T
2T/2T/9T 2T
5T/7T 5T 1.5T/1.5T/9T 1.5T
5T/6T 5T 1T/1T/9T 1T
TM
)
American Magnetics, Inc. Multi-Axis (MAxesTM) systems
allow the user to easily program an infinite number of high
magnetic field vectors. Our combination of user friendly
electronics, reliable cryogenic vessels, and robust multiaxis superconducting magnets combine to make our
MAxesTM systems an excellent choice for any application
where the outcome is dependent on precise magnetic field
vector orientation. Transport studies on anisotropic
materials at high magnetic fields & low temperatures have
revealed many exciting properties. Even though anisotropic
magneto resistance is a century old phenomena,
advancements in nanotechnology has created increased
importance to attain precision angular control, while
positioning samples in magnetic field. There has been
Cartesian, cylindrical, or spherical coordinates (2-Axis in Cartesian or polar). Once the desired vectors are
specified in tabular format or as read from a file, a “NEXT VECTOR” control from the program initiates
appropriate control commands to the AMI power supply programmers which are connected via an RS232/GPIB or an Ethernet port.
MAxesTM MX-2 (2-axis) Vector Magnet System
Forces in such magnets can be extremely high due to the
interaction between each coil when they are energized
simultaneously. Care must be taken to stay within the
factory defined operating envelop or one could end up
damaging the magnet and cryostat. This risk is minimized
by operating multiple coils of the MAxesTM system using
AMI’s Free LabVIEW virtual interface which allows the
users to specify and control the magnetic field vector from a
single computer screen. High resolution power supplies are
computer controlled using an AMI model 430 power supply
programmer. The programmer is also web enabled using an
Ethernet option. Infinite combinations of magnetic field
vectors are hence possible. Calculated field components,
based on actual current measurements and predetermined
coil constants for a given magnet, are continuously
displayed on the screen. The interface allows the users to
enter in the desired field vector of a 3-axis magnet in
Over the last few years American Magnetics has delivered wide
ranging 2-axis systems with vector fields ranging from 1T to 5T.
These have been offered for different bore sizes for use with He3
inserts and dilution fridges. American Magnetics has excellent
working relationships with various OEM’s and we work diligently to
offer customized solutions. With the advent of high power pulse tube
cryocooler technology, Cryogen free magnet systems are becoming
virtual research laboratories in various branches of condensed matter
physics. AMI offers cryogen free MAxesTM systems in both dry and
recondensing geometry. The picture on the left shows a conduction
cooled MAxesTM magnet integrated with dilution refrigerator
manufactured by Leiden Cryogenics. It is a 2-axis 3T/9T conduction
cooled magnet and offers 3T vector field with 9T in vertical plane.
Users desiring to use existing inserts that operate in liquid He may
opt for Recondensing style systems. The recondensing configuration
produces Near Zero He Boil-off systems (NZHB) and allows users to
benefit from the latest technology without investing in new and
expensive sample insert.
A typical MAxesTM-2 VTI based system has the following features:
• 2-axis magnetic field vector magnet with vertical access.
• Low-loss liquid helium cryostat with top loading sample insert with variable temperature from <2K to
400K
• 3.0 Tesla vector field in any direction with up to 12.0 Tesla in vertical axis
• 4-quadrant power supplies and web enabled magnet controllers for fast ramping capability
• Cryogen level instrumentation
• Two channel temperature controller
• Color coded, quick-disconnect power cables (e.g., no tools required)
• Pumping station for variable temperature insert (VTI)
• System software interface for magnet control (LabVIEW TM)
• Integrated instrumentation console and associated cables
• Customized system manual
MAxesTM MX-3 (3-axis) Vector Magnet System
Over the last year American Magnetics has delivered many unique MAxesTM systems. This includes the
world’s first Nb3Sn high field vector system as well as Cryogen free MAxesTM system. The high field 3axis system produced 12T in vertical plane combined with two 1T split coils in the horizontal plane. It
could also be run with peak fields of 1T, 1T and 9T simultaneously. The cryogen free MAxesTM shown
below produced 1T vector field with a 100 mm room temperature bore. These systems are being offered
with either a GM or pulse tube 4K cryocooler. For users desiring lower vibration, a pulse tube cryocooler
has been used & in these cases the cryocooler is mounted using bellows assembly while the motor is
mounted remotely.
Typical VTI based liquid helium cooled MX-3 systems have specifications similar to the ones listed for two axis
geometries. There are numerous benefits from cooling large magnets with liquid Helium. Most customers prefer
fast ramping of various coils and desire very low levels of vibration. Near Zero He Boil off recondensing style
systems offers such benefits. A ReCon MAxesTM with VTI or other inserts are one of the most desired options by
our users. Our standard product offerings includes such a system wherein a MAxesTM magnet is mounted in
ReCon style dewar and He gas from the VTI or the insert is cycled back into the Dewar using an oil free or “dry”
scroll pump. Any loss of LHe is easily compensated for by the introduction of gaseous Helium.
Opti-MAxesTM
Opti-MAxesTM systems provide variable magnetic field on two or
three principal axes and optical access in two orthogonal planes. These
are particularly useful for orientation studies on a variety of samples
for optical & beam line applications. In light of the growing interest in
spin-related phenomena and new generation devices for processing
information, there is now renewed interest in the science and
engineering of magnetic semiconductors. Magneto-optic studies
provides an ideal means for studying properties of magnetic
semiconductors and other materials where spin related phenomena are
of paramount importance. The system is comprised of a 2 or 3-axis
superconducting magnet, low helium consumption current leads,
magnet Dewar, optical windows, and associated electronics. Typical
specifications include magnetic fields up to 4T for the principal
vertical axis, 1T rotating vector using any combination of x, y and zaxis magnets. These are typically offered for 1.0” OD sample tube.
Systems with re-entrant bore tubes are also supplied. Wide varieties of
combinations are possible. The system is supplied with a variable
temperature insert which operates from <2K to 300K.
available in ReCon style NZHB system.
These are also
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