Halbach arrays are just a pattern or orientation of magnets that biases the total magnetic field to one direction.[1]

Polymagnets are just magnets with a pattern of multiple north-south poles on one face. [2]

At best you could have a Halbach array on a single polymagnet and have it be just as effective as individual magnets in the same pattern.

Though for large scale applications there wouldn't be much point as you could just use cheaper off the shelf magnets.

[1] https://www.kjmagnetics.com/images/blog/halbachvsalt.png [2] https://i.imgur.com/Nz9QJTV.png

I think the point of polymagnets aren't to maximize the magnetic attraction in one specific direction but to allow for custom magnetic field designs. From what their site says, it appears as if they are just controlling in fine detail which parts of a face of a magnet point north and which point south. Pointing sideways inside the magnet might not be possible for their equipment. Its probably easier and cheaper to just assemble arrays of regular neodymium to create the Halbach array than using something like polymagnets.

> I think the point of polymagnets aren't to maximize the magnetic attraction in one specific direction but to allow for custom magnetic field designs.

Getting strong magnets in one specific direction is one of their applications. See the "attach" example of their /polymagnets page[1]:

"Polymagnets are the world’s strongest magnets because their magnetic energy has been concentrated near the surface. Polymagnets are up to 5x stronger than conventional magnets."

1. http://www.polymagnet.com/polymagnets/